The present invention relates to an apparatus and method for fluid analysis. Particular embodiments of the present invention relate to systems and techniques for X-ray fluorescence analysis of fluids. Still more particular embodiments are related to on-board X-ray analysis of operating machine fluids for the determination of machine health.
It is well known that chemical and physical analysis of a machine fluid can provide information about the condition of the fluid as well as the wear status of the machine in which the fluid is used. Machine fluid analysis is widely used for determination of lubricant condition, lubricant contamination and wear status in engines, drive components and hydraulic systems in fleet or industrial service. For example, lubrication oil analysis is widely used for railroad engines and is conducted by the military on most motorized equipment including aircraft and naval engines and lubricated drive components. In industry, commercial fluid analysis providers offer fluid analysis service for engine and drive train lubricants as well as hydraulic fluids.
However, traditionally, an oil sample has been taken from the lubricant reservoir on the engine being analyzed, with fluid parameters then measured in the laboratory. To avoid inefficiencies and difficulties associated with such batch analysis, it is desirable to develop systems and devices capable of operation on board a machine to provide continuous and real time monitoring of machine fluids.
One type of fluid analysis, X-ray fluorescence analysis, has the potential to be used to quantify trace amounts of materials in machine fluids, provided the X-ray fluorescence meter employed is sufficiently sensitive to the material to be detected. However, for a variety of reasons, current X-ray fluorescence meter designs are not readily applicable for on-board machine fluid analysis.
For example, while not as important for most laboratory scale spectrometer applications, for an on-board machine fluid application, it is advantageous to have a compact spectrometer. However, the sensitivity of a spectrometer is typically compromised by attempts to limit its size because, as the device becomes smaller, components necessarily get closer together, increasing the relative significance of noise. In addition, a smaller device may be more susceptible to breaking or failure from the potentially harsh environment on-board a machine. As a final example, in order to be feasible for dedicated application to individual machines, an X-ray fluorescence meter must be economical to manufacture.
Therefore, a need exists for an X-ray fluorescence spectrometer that is both compact and sensitive so as to be useful in on-board machine fluid analysis. A need also exists for an X-ray fluorescence spectrometer that is capable of meeting the rigors of on-board application yet is economical and efficient to construct.
The present invention addresses one or more of these or other needs and provides, in one embodiment, a novel X-ray fluorescence spectrometer. Another embodiment provides a novel method of performing X-ray fluorescence analysis of fluids. Still other embodiments provide improved systems and techniques useful in on-board machine fluid analysis.
The invention is set forth in the claims below, and the following is not in any way to limit, define, or otherwise establish the scope of legal protection. In general terms, the present invention relates to X-ray fluorescence analysis of fluids, where one particular application of the invention involves X-ray analysis of machine fluids to thereby provide an indication of engine health.
In one embodiment a novel X-ray fluorescence meter is disclosed including a source block containing an X-ray source, a substantially X-ray transparent fluid flow path through the source block and proximate the X-ray source, and a fluorescence X-ray detector mounted to the source block proximate the flow path and separated from the X-ray source by the source block. The source block includes first and second openings between the X-ray source and the flow path and between the flow path and the detector respectively, and the source block defines a noise reduction cavity having an opening thereto adjacent the flow path and opposite the X-ray source. In operation, source X-rays pass through the first opening and through the flow path. A portion of the source X-rays interact with a fluid in the flow path to create a fluid fluorescence response. The remainder of the source X-rays pass into the noise reduction cavity. The detector receives the portion of the fluid fluorescence response passing through the second opening and produces an output indicative of the presence and amount of selected components in the fluid. In one refinement a substantial portion of the source block is material having elements with an atomic number below the atomic number of the element(s) to be detected. In this and in other refinements, the source block is contained in a rigid outer housing including a pair of fluid couplings coupled to the flow path. In any of the above or in still further refinements one or more layers of X-ray shielding material are placed around the source block and/or between the detector and the source block.
In another embodiment there is described herein a novel X-ray fluorescence spectrometer including a source block containing an X-ray source and having a fluid flow path therethrough proximate the X-ray source. The flow path is substantially transparent to source X-rays and is operable to direct a fluid past the X-ray source for interaction of the fluid with source X-rays to produce a fluid fluorescence response to the source X-rays. The spectrometer includes a detector mounted proximate the flow path for receiving at least a portion of the fluorescence response for quantitatively determining the presence of selected components of the fluid. In any refinement, the source block is formed of material comprising elements having a low atomic number such as magnesium, graphite, aluminum, or plastic. In the above or in a further refinement a rigid outer housing surrounds the source block and includes a pair of fluid couplings connected to the flow path for coupling the flow path to a machine fluid line. In any of the above or in still further refinements, the source block defines a noise reduction cavity separated from the detector by the source block and operable to receive source X-rays passing through the flow path. The noise reduction cavity has an opening thereto adjacent the flow path and opposite the X-ray source such that the flow path is between the cavity opening and the X-ray source. In any of the above or in further refinements, one or more layers of X-ray shielding is provided around the source block and/or between the detector and the source block. In any of the above or in further refinements the detector has a detection face substantially parallel to the flow direction for fluid in the flow path. In any of the above or in still further refinements, the detector, the X-ray source, and the flow path proximate the X-ray source form a plane perpendicular to the fluid flow path through the source block.
In another embodiment, a novel method of performing fluid analysis is provided including providing an X-ray fluorescence meter including a source block containing an X-ray source and having a fluid flow path past the X-ray source, passing fluid through the flow path, passing source X-rays through the flow path and into a noise reduction cavity of the source block, and receiving a fluid fluorescence response to the source X-rays with a detector isolated from source X-rays by the source block. In one refinement, the fluid is machine fluid and is passed through the flow path under pressure of a machine. In this or in other refinements, the detected fluorescence response travels in a direction substantially perpendicular to the bulk fluid flow direction and/or in a direction substantially perpendicular to source X-rays passing through the flow path. In any of the above or in further refinements, the source block in contained in a rigid outer housing having a pair of fluid couplings for coupling the fluid through the flow path.